TECHNICAL FIELD
[0001] The present invention relates to a process for preparing a condensed phosphoric ester.
More specifically, the present invention relates to a process for preparing a condensed
phosphoric ester having a low content of volatile components, which is excellent as
a flame retardant for resins.
BACKGROUND ART
[0002] Conventionally, various types of flame retardants are used for flame retardation
of inflammable plastic materials, for example, halogen compounds such as decabromobiphenylether
and tetrabromobisphenol A, and low molecular weight phosphorus compounds such as cresyl
diphenyl phosphate and triphenyl phosphate.
[0003] Today, resin compositions are required to be non-halogenic from an environmental
point of view, for example, due to the hazardous effects of dioxin. Flame retardants
containing heavy metals cause problems due to their toxicity. Under these circumstances,
phosphorus-based flame retardants have now become a target of attention. Among the
phosphorus-based flame retardants, aromatic phosphoric ester-based flame retardants
are a target of attention for their effectiveness especially in the applications of
engineering plastics such as PC/ABS alloys and modified PPE since they have little
adverse influence on the environment as well as superb physical properties. Actually,
the industrial demand for phosphorus-based flame retardants, especially aromatic phosphoric
ester-based flame retardants, is good and continues to increase at a high rate.
[0004] However, engineering plastics are molded at a very high temperature and therefore
the following problems have occurred. When a low molecular weight monomer-type phosphoric
ester such as triphenyl phosphate (TPP) or tricresyl phosphate (TCP) is used, the
monomer-type phosphoric ester is thermally decomposed, bleeds out or volatizes during
the molding process, which causes defective molding, contamination of the molds or
the like.
[0005] It is known that use of a high molecular weight condensed phosphoric ester as a flame
retardant is effective for avoiding these problems.
[0006] WO97/47631 discloses a process for preparing an aryldiphosphate ester by initially
reacting aphosphoryl oxyhalide with a dihydric aromatic compound in the presence of
an insoluble catalyst to form an intermediate. The intermediate is then reacted with
a monohydric aromatic compound in the presence of an insoluble catalyst to form the
aryldiphosphate ester, after which the catalyst is filtered from the product. In a
first Example, bisphenol A tetrachlorodiphosphate is formed as an intermediate by
reacting 4,4'-isopropylidenediphenol with 3.6 mol times the amount of phosphorus oxychloride
in the presence of calcium chloride as catalyst. The intermediate is reacted with
phenol also in the presence of calcium chloride at 180°C, after which the temperature
is raised to 240°C and additional phenol was added. The product was a viscous light
yellow liquid containing bisphenol A tetraphenyl diphosphate (81%) and triphenyl phosphate
(3.6%). In the second and third examples, the contents of triphenyl phosphate in the
product were 7% and 4%.
[0007] Japanese Laid-Open Publication No. 63-227632 discloses a process for preparing a
condensed phosphoric ester. According to this process, a condensed phosphoric ester
is prepared by reacting a dihydroxy compound such as resorcin, hydroquinone, bisphenol
A or the like with phosphorus oxychloride, thereafter removing unreacted phosphorus
oxychloride, and then reacting the resultant product with phenol, cresol, xylenol
or the like.
[0008] This process can reduce, to some extent, monomer-type phosphoric ester which is generated
by the reaction between phosphorus oxychloride and a monophenol-based compound contained
in the condensed phosphoric ester.
[0009] However, this process has the following problem. In the case where a condensed phosphoric
ester is produced using a bisphenol A derivative as a starting material, especially
on an industrial scale, the bisphenol A derivative is decomposed during the reaction
and thus an isopropenyl aryl group-containing phosphate (hereinafter, referred also
to as an "IPP") such as, for example, isopropenyl phenyl diphenyl phosphate is likely
to be produced. This is likely to result in reduction in heat resistance, coloring-related
problems of products, and reduction in moldability caused by the contamination of
molds.
[0010] The process described in Japanese Laid-Open Publication No. 63-227632 also has the
problem that a significant amount, specifically about 4 to 7% by weight of monomer-type
phosphoric ester is contained as an impurity, especially when the production is performed
on an industrial scale. Therefore, the monomer-type phosphoric ester still volatizes
or bleeds out, which causes defective molding, the contamination of the molds or the
like. As such, it is difficult to obtain a satisfactory molding efficiency.
[0011] Accordingly, production of a condensed phosphoric ester, especially on an industrial
scale, requires that many conditions including the ratio of materials, reaction temperature,
and reaction time should be carefully selected in order to reduce the content of the
IPP and the monomer-type phosphoric ester as impurities.
[0012] Until today, details of such conditions have not been studied, and thus the relationship
between the conditions and the amount of impurity in the resultant product has not
been clarified at all. Especially regarding the ratio of materials, the use of ratios
that are obtained by theoretical calculations based on stoichiometry or slightly greater
ratios has been considered to be the most efficient way to reduce the impurity. Therefore,
the ratios obtained by stoichiometric calculations have been loyally adopted. For
the reaction temperature, a relatively high temperature has been adopted for the purpose
of raising the reaction speed.
(Problems to be Solved by the Invention)
[0013] An objective of the present invention is to solve the above-described problems by
providing a process for preparing a condensed phosphoric ester formed from a bisphenol
A derivative as a starting material, having a low content of IPP and monomer-type
phosphoric ester as impurities. Another objective of the present invention is to enhance
the quality of resin-molded products by using the condensed phosphoric ester produced
by a process according to the present invention as a flame retardant, so as to make
a contribution to the society.
DISCLOSURE OF THE INVENTION
(Means for Solving the Problems)
[0014] As a result of active studies, the present inventors found that the above-described
problems can be solved by a process for preparing a condensed phosphoric ester, including
a first step of reacting a bisphenol A derivative with a phosphorus oxytrihalide in
an amount equal to or greater than 4.5 mol times the amount of the bisphenol A derivative
to prepare a phosphorohalidate; a second step of removing unreacted phosphorus oxytrihalide;
a third step of reacting the reaction product obtained in the second step with a monophenol-based
compound at a temperature equal to or lower than 120°C; and a fourth step of reacting
the phosphorohalidate with the monophenol-based compound at a temperature equal to
or higher than 120°C. Thus, the present inventors completed the present invention.
[0015] The present invention provides the following processes.
1. A process for preparing a condensed phosphoric ester, comprising:
a first step of reacting a bisphenol A derivative with a phosphorus oxytrihalide in
an amount equal to or greater than 4.5 mol times the amount of the bisphenol A derivative
to prepare a phosphorohalidate;
a second step of removing unreacted phosphorus oxytrihalide after the first step;
a third step of reacting the reaction product obtained in the second step with a monophenol-based
compound at a temperature equal to or lower than 120°C; and
a fourth step of reacting the phosphorohalidate with the monophenol-based compound
at a temperature equal to or higher than 120°C.
2. A process according to above-described item 1, wherein the total amount of the
monophenol-based compound used in the third step and the fourth step is greater, by
equal to or less than 2 mol%, than the theoretically necessary amount for turning
the entire amount of the phosphorohalidate into the condensed phosphoric ester.
3. A process according to above-described item 1 or 2, wherein the condensed phosphoric
ester is 2,2-bis{4-[bis(phenoxy)phosphoryl]oxyphenyl}propane.
BEST MODE FOR CARRYING OUT THE INVENTION
[0016] Hereinafter, the present invention will be specifically described.
(First step)
[0017] In the first step, a phosphorus oxytrihalide and a bisphenol A derivative are reacted,
thereby preparing a phosphorohalidate.
[0018] Examples of the phosphorus oxytrihalide include phosphorus oxychloride and phosphorus
oxybromide.
[0019] The bisphenol A derivative refers to bisphenol A or a derivative thereof, which is
represented by the following formula (A):
(where R
5 and R
6 are the same as or different from each other and represent an alkyl group containing
1 to 3 carbon atoms; and n1 and n2 each represent an integer from 0 to 4).
[0020] In the present invention, a phosphorohalidate refers to a compound represented by
the following formula (I):
(where X represents a halogen atom; n represents an integer from 1 to 10; and R
5, R
6, n1 and n2 each refer to the same as above.)
[0021] According to conventional, general technical knowledge, it is considered to be non-preferable
that the amount of the phosphorus oxytrihalide is greater than a stoichiometrical
reaction amount which is calculated from the amount of the bisphenol-based compound,
i.e., 2 mol times the amount of the bisphenol-based compound. The reason is that the
amount of remaining unreacted phosphorus oxytrihalide necessarily increases, which
complicates the operation for recovering the unreacted phosphorus oxytrihalide. According
to the present invention, however, the amount of the phosphorus oxytrihalide is equal
to or greater than 4.5 mol times, more preferably equal to or greater than 5 mol times,
and still more preferably equal to or greater than 5.4 mol times the amount of the
bisphenol A derivative. By using such excessive amounts of phosphorus oxytrihalide,
an unexpected advantage that the decomposition of the bisphenol A derivative is suppressed
is obtained, which is quite surprising.
[0022] Here, "mol times" refers to the ratio based on the mol value.
[0023] When the relative amount of the phosphorus oxytrihalide to the amount of bisphenol
A derivative is insufficient, the amount of the IPP, which is produced by decomposition
of the bisphenol A derivative by a hydrogen halide produced as a by-product of the
reaction of the phosphorus oxytrihalide and the bisphenol A derivative, increases.
[0024] The upper limit of the amount of the phosphorus oxytrihalide cannot be determined.
When the amount of the phosphorus oxytrihalide is excessive, an unnecessarily large
amount of phosphorus oxytrihalide needs to be removed in the second step described
below, and decreases the operation efficiency in the reactor and also the productivity.
The phosphorus oxytrihalide is usually used in an amount equal to or less than 8 mol
times, and more preferably equal to or less than 6 mol times the amount of the bisphenol-based
compound. Still more preferably, the amount of the phosphorus oxytrihalide and the
bisphenol A derivative are adjusted within the above-mentioned ranges so that the
concentration of the hydrogen halide in the reaction solution is equal to or less
than 5%.
[0025] According to the present invention, a catalyst can be used. Usable catalysts include,
for example, Lewis acid-based catalysts such as aluminum chloride, magnesium chloride
and titanium tetrachloride.
[0026] The other conditions, for example, the reaction temperature, reaction time and reduction
in pressure can be appropriately selected in accordance with the type of the intended
condensed phosphoric ester, condensation degree, and type and scale of the apparatus
used. The temperature is preferably 80 to 130°C, and more preferably 80 to 120°C.
It is acceptable to start with a temperature lower than 80°C and then raise the temperature
to 80 to 130°C. For example, it is acceptable to start with room temperature and then
raise the temperature to 80 to 130°C. The reaction time is preferably 3 to 20 hours.
Hydrogen halide gas generated by the reaction is preferably captured by water.
[0027] An organic solvent can be used when necessary although it is not usually necessary.
For example, aromatic group-based organic solvents including toluene, xylene, and
dichlorobenzene and aliphatic group-based organic solvents including hexane and heptane
are usable.
[0028] When it is necessary to prevent the resultant product from being colored, a phosphorus-based
compound such as, for example, triphenyl phosphite or tri(2,6-di-t-butyl) phosphite;
a hindered phenol-based compound such as, for example, 2,6-di-t-butyl-p-cresol (BHT)
or 2-methyl-6-t-butyl-p-cresol; or the like can be added as a coloring prevention
agent.
[0029] In the first step, a small amount of IPP is usually produced as a by-product. After
the first step, operations only for removing the residual IPP, for example, purification
by chromatography, can be performed. However, the process according to the present
invention allows the second step to be performed without conducting any specific operation
only for removing the IPP.
(Second step)
[0030] In the second step, the phosphorus oxytrihalide remaining unreacted after the first
step is removed.
[0031] The removal of the phosphorus oxytrihalide can be performed using any known method.
[0032] The removal of the unreacted phosphorus oxytrihalide is usually performed at normal
pressure or under reduced pressure. Performing the third step described below in the
state where the phosphorus oxytrihalide is not sufficiently removed, i.e., in the
state where phosphorus oxytrihalide remains, causes generation of a monomer-type phosphoric
ester. Therefore, it is preferable to remove and recover the maximum possible amount
of the phosphorus oxytrihalide. Preferable conditions for removing and recovering
the phosphorus oxytrihalide are, for example, as follows. The pressure is reduced
to equal to or less than 200 mmHg, more preferably equal to or less than 100 mmHg,
and still more preferably equal to or less than 50 mmHg, by a vacuum pump. The recovery
temperature is preferably 100 to 200°C, more preferably 100 to 170°C, and still more
preferably 100 to 150°C.
[0033] In the reaction product after the second step, usually, a part of the IPP produced
as a by-product in the first step remains. After the first step, operations only for
removing the residual IPP, for example, purification by chromatography can be performed.
However, the process according to the present invention allows the second step to
be performed without conducting any specific operation only for removing the IPP.
(Third step)
[0034] In the third step, a monophenol-based compound is acted on the product obtained after
the second step, at a relatively low reaction temperature.
[0035] In the present invention, the condensed phosphoric ester refers to a compound represented
by the following formula (II):
(where R
1, R
2, R
3 and R
4 represent an identical or different aryl group containing 6 to 15 carbon atoms; and
R
5, R
6, n1, n2 and n represent the same as above.)
[0036] Examples of the aryl group containing 6 to 15 carbon atoms include phenyl, (o-, m-,
p-)methylphenyl, (o-, m-, p-)ethylphenyl, (o-, m-, p-)n-propylphenyl, (o-, m-, p-)isopropylphenyl,
(o-, m-, p-)n-butylphenyl, (o-, m-, p-)sec-butylphenyl, (o-, m-, p-)tert-butylphenyl,
(2,3-2.4-, 2,5-, 2,6-, 3,4-, 3,5-)dimethylphenyl, (2,3- 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)diethylphenyl,
2-methyl-3-ethylphenyl. 2-methyl-4-ethylphenyl, 2-methyl-5-ethylphenyl. 2-methyl-6-ethylphenyl,
3-methyl-4-ethylphenyl, 3-methyl-5-ethylphenyl, 2-ethyl-3-methylphenyl, 2-ethyl-4-methylphenyl,
2-ethyl-5-methylphenyl, 3-ethyl-4-methylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-n-propylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-,3,5-)diisopropylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-,
3,5-)di-n-butylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-sec-butylphenyl, (2,3-,
2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-tert-butylphenyl, (2,3,6-, 2,3,5-, 2,3.4-, 2,4,5-,
2,4,6-, 3,4,5-)trimethylphenyl, (2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)triethylphenyl,
(2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)tripropylphenyl, and naphtyl. Here,
"(o-, m-, p-)" indicates that substituents independently exist in either positions
of o- (ortho), m-(meta) or p- (para) on a benzene ring. "(2,3-, 2,4-, 2,5-, 2,6-,
3,4-, 3,5-)" indicates that substituents independently exist in positions 2,3-, 2,4-,
2,5-, 2,6-, 3,4-, or 3,5- on a benzene ring. "(2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-,
3,4,5-)" indicates that substituents independently exist in positions 2,3,6-, 2,3,5-,
2,3,4-, 2,4,5-, 2,4,6-, or 3,4,5- on a benzene ring.
[0037] Specific examples of the condensed phosphoric ester represented by formula (II) include
2,2-bis{4-[bis(phenoxy)phosphoryl]oxyphenyl}propane, 2,2-bis{4-[bis(methylphenoxy)phosphoryl]oxyphenyl}propane,
2,2-bis{4-[bis(dimethylphenoxy)phosphoryl]oxyphenyl}, and 2,2-bis{4-[bis(methylethylphenoxy)
phosphoryl]oxyphenyl}propane which are made from a bisphenol A derivative.
[0038] A monophenol-based compound refers to phenol or a substituted phenol containing one
phenolic hydroxyl group.
[0039] Examples of the monophenol-based compound include phenol, (o-, m-, p-)methylphenol,
(o-, m-, p-)ethylphenol, (o-, m-, p-)n-propylphenol, (o-, m-, p-)isopropylphenol,
(o-, m-, p-)n-butylphenol, (o-, m-, p-)sec-butylphenol, (o-, m-, p-)tert-butylphenol,
methylphenol, (2,3- 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)dimethylphenol, (2,3- 2,4-, 2,5-,
2,6-, 3,4-, 3,5-)diethylphenol, 2-methyl-3-ethylphenol, 2-methyl-4-ethylphenol, 2-methyl-5-ethylphenol,
2-methyl-6-ethylphenol, 3-methyl-4-ethylphenol, 3-methyl-5-ethylphenol, 2-ethyl-3-methylphenol,
2-ethyl-4-methylphenol, 2-ethyl-5-methylphenol, 3-ethyl-4-methylphenol, (2,3-, 2,4-,
2,5-, 2,6-, 3,4-, 3,5-)di-n-propylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)diisopropylphenol,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-n-butylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-,
3,5-)di-sec-butylphenol, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-tert-butylphenol.
(2,3,6-, 2,3,5-, 2,3,4-,2,4,5-, 2,4,6-, 3,4,5-)trimethylphenol, (2,3,6-, 2,3,5-, 2,3,4-,
2,4,5-, 2,4,6-, 3,4,5-)triethylphenol, (2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)tripropylphenol,
and naphtol. Phenol is especially preferable. One monophenol-based compound or a combination
of two or more monophenol-based compounds can be used.
[0040] In the present invention, a monomer-type phosphoric ester refers to a triester produced
by the reaction of a phosphorus oxytrihalide and a monophenol-based compound. Specific
examples of the monomer-type phosphoric ester include triphenyl phosphate when the
monophenol-based compound is, for example, phenol; tricresyl phosphate [(o-, m-, p-)methylphenyl
phosphate] when the monophenol-based compound is cresol [(o-, m-, p-)methylphenol];
and trixylyl phosphate [(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)dimethylphenyl phosphate]
when the monophenol-based compound is xylenol [(2,3-, 2,4, 2,5-, 2,6-, 3,4-, 3,5-
)dimethylphenol]
[0041] In the third step, the reaction temperature needs to be equal to or lower than 120°C,
preferably equal to or lower than 110°C, more preferably equal to or lower than 105°C,
and especially preferably equal to or lower than 100°C.
[0042] By adopting such a relatively low temperature, a portion of the monophenol-based
compound reacts with the IPP contained in the reaction mixture generated after the
second step. As a result, the IPP is removed.
[0043] When the reaction temperature is too high, the monophenol-based compound reacts with
the phosphorohalidate with priority, and therefore the reaction of the monophenol-based
compound and the IPP is unlikely to sufficiently proceed. Therefore, the amount of
the IPP is unlikely to be sufficiently reduced.
[0044] The lower limit of the reaction temperature is not specifically determined. Notably,
a temperature at which the IPP and the monophenol-based compound can contact each
other efficiently without a dehydrohalogenation reaction being caused is preferable.
The lower limit of the reaction temperature is appropriately determined based on the
combination of the type and amount of the monophenol-based compound, the speed at
which the monophenol-based compound is added, the reaction scale, and other reaction
conditions (e.g., reaction time, reduction in pressure, whether a solvent is used
or not). The lower limit of the reaction temperature is preferably, for example, equal
to or higher than 40°C, more preferably equal to or higher than 60°C, and still more
preferably equal to or higher than 80°C.
[0045] The time period for the third step is preferably 30 minutes to 8 hours, and more
preferably 1 to 6 hours.
(Fourth step)
[0046] According to the present invention, the fourth step is performed for further reaction
after the third step. The fourth step is performed at an elevated temperature equal
to or higher than 120°C. The temperature for the fourth step is preferably 120 to
170°C and more preferably 140 to 160°C.
[0047] The time for the fourth step is preferably 10 minutes to 5 hours, more preferably
30 minutes to 5 hours, still more preferably 30 minutes to 4 hours, and especially
preferably 1 to 3 hours.
[0048] Preferably, the reaction temperature in the third step is increased to the reaction
temperature in the fourth step, over 30 minutes to 8 hours and more preferably 1 to
6 hours.
[0049] The total amount of the materials used in the third step and the fourth step is preferably
added before the third step is started. When necessary, a portion of the materials
can be added during the third step, between the third step and the fourth step, or
during the fourth step. The "amount of the reactive materials" used in the third step
and the fourth step described in this specification refers to the total amount of
the materials added before the completion of the fourth step.
[0050] In a preferred embodiment, the amount of the monophenol-based compound is greater
by an excess ratio of equal to or less than 2 mol% than the amount which is theoretically
necessary for turning the entire amount of the phosphorohalidate contained in the
reaction mixture after the second step into a condensed phosphoric ester.
[0051] In this embodiment, the production of a monomer-type phosphoric ester as a by-product
which is caused by interesterification of the condensed phosphoric ester produced
and the monophenol-based compound can be suppressed without reducing yield or quality.
Considering that interesterification of the condensed phosphoric ester and the monophenol-based
compound is likely to occur especially in industrial, large scale production due to
the long reaction time, the process of the present invention which can suppress the
production of a monomer-type phosphoric ester as a by-product is very advantageous.
[0052] Here, the term "industrial scale" indicates that the total amount of the monophenol-based
compound and the phosphorohalidate which are reacted with each other is an amount
used in usual industrial production. Specifically, industrial scale is preferably
equal to or greater than 5 liters, more preferably equal to or greater than 30 liters,
still more preferably equal to or greater than 100 liters, and especially preferably
equal to or greater than 300 liters.
[0053] The total amount of the monophenol-based compound and the phosphorohalidate which
are reacted with each other is specifically preferably equal to or less than 20000
liters, and more preferably equal to or less than 10000 liters due to restrictions
caused by, for example, the reaction apparatus.
[0054] When the amount of the monophenol-based compound is smaller than the theoretical
amount stoichiometrically calculated, unreacted phosphorohalidate will inevitably
remain, which is likely to cause problems which complicate the purification and post-processing
steps.
[0055] When the amount of the monophenol-based compound is the theoretical amount stoichiometrically
calculated, the reaction is likely to be incomplete. As a result, unreacted phosphorohalidate
remains, which is likely to cause the problems of, for example, the phosphorohalidate
remaining in the product as an impurity or complicating the purification and post-processing
steps.
[0056] An excess amount of the monophenol-based compound is not preferable since the amount
of the monomer-type phosphoric ester produced as a by-product is increased. Therefore,
the monophenol-based compound is preferably greater than the stoichiometrically theoretical
amount by equal to or less than 2.0 mol%, more preferably equal to or less than 1.8
mol%, still more preferably equal to or less than 1.6 mol%, and especially preferably
equal to or less than 1.5 mol%.
[0057] The stoichiometrically theoretical amount necessary for turning the entire amount
of the phosphorohalidate into a condensed phosphoric ester refers to the amount which
is necessary for substituting all the halogen atoms contained in the phosphorohalidate
with arylester groups. For example, in the case where n=1 in formula (I) above, such
an amount of the monophenol-based compound is 4 mol with respect to 1 mol of the phosphorohalidate.
In the case where n=2, such an amount of the monophenol-based compound is 5 mol with
respect to 1 mol of the phosphorohalidate. In the case where n=3, such an amount of
the monophenol-based compound is 6 mol with respect to 1 mol of the phosphorohalidate.
[0058] Here, the excess ratio is a value obtained by subtracting the stoichiometrically
theoretical mol value from the used mol value of the monophenol-based compound, dividing
the resultant value by the stoichiometrically theoretical mol value to obtain a ratio,
and then multiplying the ratio by 100 so as to be represented by a percentage.
[0059] The lower limit of the amount of the monophenol-based compound cannot be exactly
determined since it varies in accordance with, for example, the type of the condensed
phosphoric ester and the reaction conditions. The lower limit is preferably equal
to or greater than 0.2 mol%, more preferably equal to or greater than 0.3 mol%, especially
preferably equal to or greater than 0.4 mol%, and still more preferably equal to or
greater than 0.5 mol%.
[0060] The other reaction conditions (e.g., the reduction in pressure and the time to add
the monophenol-based compound) are appropriately selected as desired.
[0061] The hydrogen halide generated during the reaction and remaining after the reaction
is preferably recovered at normal pressure or low pressure. The hydrogen halide can
be, for example, captured by water to be recovered.
[0062] A condensed phosphoric ester prepared in this manner usually contains a great amount
of impurities including partially reacted components, unreacted components, and remaining
catalysts. Therefore, the impurities are removed from the crude condensed phosphoric
ester by known purification methods such as neutralization, water rinsing, steam distillation
or the like.
[0063] When, for example, a method using an epoxy compound is adopted for purification,
the epoxy compound is added to an -OH group of a partially reacted component and then
selective hydrolysis is performed. Thus, the partially reacted product can be converted
into phosphoric acid. By washing the phosphoric acid with hot water, the phosphoric
acid components can be removed so as to reduce the acid value of the product.
[0064] A product obtained in this manner is a high quality condensed phosphoric ester having
a very low content of IPP and monomer-type phosphoric ester.
[0065] Such a high quality condensed phosphoric ester can be used for various types of resins
as a flame retardant.
[0066] Specifically, the high quality condensed phosphoric ester can be used for, for example,
the following resins: thermoplastic resins such as polyethylene-based resins, polypropylene-based
resins, polybutadiene-based resins, polystyrene-based resins, polyphenylene ether-based
resins, polycarbonate-based resins, ABS (acrylonitrile-butadiene-styrene)-based resins,
high impact styrene-based resins, SAN (styrene-acrylonitrile)-based resins, polyamide-based
resins, polyester-based resins, polyphenylene sulfide-based resins, polyacrylic resins,
polymethacrylic resins, and the like; and thermosetting resins such as epoxy-based
resins, polyurethane-based resins, polyimide-based resins, phenol-based resins, novolac-based
resins, polyetherimide-based resins, melamine-based resins, urea-based resins and
the like.
[0067] A condensed phosphoric ester obtained by a process of the present invention can be
especially advantageously used for a resin having a high molding temperature, for
example, a resin moldable at a temperature of equal to or higher than 160°C in one
embodiment, a resin moldable at a temperature of equal to or higher than 180°C in
a more preferable embodiment, and a resin moldable at a temperature of equal to or
higher than 200°C in an especially preferable embodiment.
[0068] When a condensed phosphoric ester obtained by a process of the present invention
is added to any of the above-listed resins as a flame retardant, a high quality molded
product having excellent resistance against heat and resistance against coloring can
be obtained without generating gas despite the high process temperature during the
molding process of the resin using a molding apparatus.
[0069] A condensed phosphoric ester obtained by a process of the present invention is added
to a resin and molded. As result, any desired flame retardant molded product is provided.
[0070] For adding the flame retardant to the resin and for molding the resin supplied with
the flame retardant, any known method is usable.
[0071] For example, the components (e.g., the resin, flame retardant, plasticizer, flame-retarding
adjuvant, releasing agent, ultraviolet absorbing agent, anti-oxidant, light-shielding
agent, weather resistance improving agent, and inorganic filler) can be melted and
kneaded using a multi-purpose kneading apparatus such as a single-screw extruder,
a twin-screw extruder, a Banbury mixer, a kneader, a mixer, a roll or the like and
mixed with each other. Alternatively, a molding apparatus such as an extruding molding
apparatus can be used to produce a plate-like, sheet-like, or film-like molded product.
Thus, a desired molded product is obtained.
(Examples)
[0072] Hereinafter, preferable examples of the present invention will be described, but
the present invention is not limited to these examples.
[0073] In the examples, the content of the monomer-type phosphoric ester in each product
was measured by high-performance liquid chromatography (device: LC10AD, column: SilicaODS-80TM,
oven: CTO-10A, eluant: methanol:water = 8:2 (v/v), flow rate: 0.8 ml/min., detector:
SPD10A, UV frequency of the detector: 254 nm). In the examples, "%" represents "%
by weight" unless otherwise specified.
(Example 1)
[0074] An 8000 L reaction device including a stirrer, a thermometer, a dripper, a hydrochloric
acid recovery device and a condenser (30°C) was filled with 6631 kgs (43.2 kmol) of
phosphorus oxychloride, 1827 kgs (8 kmol) of bisphenol A and 18.4 kgs of magnesium
chloride. These materials were heated to 105°C over 6 hours while being stirred, and
then reacted for another 3 hours. Hydrochloric acid generated was recovered by the
hydrochloric acid recovery device (amount recovered: 556 kgs).
[0075] Then, treatment was performed at a temperature of 130°C and a pressure of 50 mmHg
for 5 hours in a nitrogen atmosphere. As a result, unreacted phosphorus oxychloride
(4195 kgs) was recovered. The concentration of chlorine in the resultant reaction
mixture was 30.4%.
[0076] 2994 kgs (excess ratio: 1%) of phenol was added to 3683 kgs of the resultant reaction
mixture over 6 hours at 100°C and normal pressure, then the temperature was raised
to 150°C over 4 hours, and the reaction was continued for another 1 hour for aging.
Hydrochloric acid generated was recovered by the hydrochloric acid recovery device
(amount recovered: 1125 kgs). Then, the hydrochloric acid remaining in the system
was completely removed at 150°C and 10 mmHg over 1 hour. Thus, 5564 kgs of crude condensed
phosphoric ester was obtained.
[0077] The crude condensed phosphoric ester was diluted with toluene and then washed with
an aqueous solution of diluted hydrochloric acid. Then, the organic phase containing
the crude condensed phosphoric ester was treated with propylene oxide. After the resultant
substance was repetitively rinsed with water, toluene was recovered by distillation
under reduced pressure. Then, unreacted phenol was removed by steam distillation.
As a result, 5385 kgs of condensed phosphoric ester (2,2-bis{4-[bis(phenoxy)phosphoryl]oxyphenyl}propane)
was obtained. The content of the IPP in the resultant product was 0.035%, the content
of the monomer-type phosphoric ester (TPP) in the resultant product was 1.6%, and
the acid value ( KOH/mg ) thereof was 0.035.
(Comparative example 1)
[0078] A condensed phosphoric ester was prepared in a similar process to that of the example
except that the amount of the phosphorus oxychloride was 4421 kgs (28.8 kmol), the
amount of the phenol was 3083 kgs (excess ratio: 4%) and the phenol was added at 150°C.
The content of the IPP in the resultant product was 2.5%, the content of the monomer-type
phosphoric ester (TPP) in the resultant product was 4.5%, and the acid value (KOH/mg)
thereof was 0.04.
(Comparative example 2)
[0079] A condensed phosphoric ester was prepared in a similar process to that of the example
except that the phenol was added at 150°C. The content of the IPP in the resultant
product was 1.3%, the content of the monomer-type phosphoric ester (TPP) in the resultant
product was 2.2%, and the acid value (KOH/mg) thereof was 0.04.
INDUSTRIAL APPLICABILITY
[0080] According to a process for preparing a condensed phosphoric ester of the present
invention, the content of the monomer-type phosphoric ester can be reduced to equal
to or less than about 3% without reducing the yield of the products. Accordingly,
a condensed phosphoric ester prepared by the process of the present invention is excellent
in heat resistance, volatility and coloring resistance. When used as a plasticizer
or a flame retardant for a resin, the condensed phosphoric ester prepared by the process
of the present invention has the advantages of preventing generation of hazardous
gas and the contamination of the molds during the molding, and reduction in the heat
resistance of the molded product. Among these advantages, improved prevention of the
contamination of the molds is industrially especially advantageous since it increases
the number of continuous shots and thus reduces the production costs.
1. A process for preparing a condensed phosphoric ester, comprising:
a first step of reacting a bisphenol A derivative with a phosphorus oxytrihalide in
an amount equal to or greater than 4.5 mol times the amount of the bisphenol A derivative
to prepare a phosphorohalidate;
a second step of removing unreacted phosphorus oxytrihalide after the first step;
a third step of reacting the phosphorohalidate obtained in the second step with a
monophenol-based compound at a temperature equal to or lower than 120°C; and
a fourth step of reacting the phosphorohalidate with the monophenol-based compound
at a temperature equal to or higher than 120°C.
2. The process of claim 1, wherein the amount of phosphorus oxytrihalide is 5-8 mol times,
preferably 5.4-6 mol. times, the amount of the bisphenol A derivative.
3. The process of claim 1 or 2, wherein the first step is carried out in the presence
of a catalyst which is aluminium chloride, magnesium chloride, titanium tetrachloride
or another Lewis acid.
4. The process of any preceding claim, wherein the third step of reacting the phosphorohalidate
with the monophenol-based compound is at a temperature of 60-110°C, preferably 80-100°C.
5. The process of any preceding claim, wherein the total amount of the monophenol-based
compound used in the third step and the fourth step is greater, by equal to or less
than 2 mol%, than the theoretically necessary amount for turning the entire amount
of the phosphorohalidate into the condensed phosphoric ester.
6. The process of any preceding claim, wherein the temperature for the fourth step is
120-170°C, preferably 140-160°C.
7. The process of any preceding claim, wherein the bisphenol A or derivative thereof
is represented by the formula:
wherein R
5 and R
6 which may be the same or different each represent an alkyl group containing 1-3 carbon
atoms and n
1 and n
2 each represent an integer from 0 to 4.
8. The process of any preceding claim, wherein the condensed phosphoric ester is a compound
represented by the formula:
wherein R
5, R
6, n
1 and n
2 have the meanings given in claim 16, n is an integer from 1 to 10 and R
1, R
2, R
3 and R
4 which may be the same or different each represent an aryl group containing 6-15 carbon
atoms.
9. The process of claim 8, wherein R
1, R
2, R
3 and R
4 each represent phenyl,
(o-, m-, p-)methylphenyl,
(o-, m-, p-)ethylphenyl,
(o-, m-, p-)n-propylphenyl,
(o-, m-, p-)isopropylphenyl,
(o-, m-, p-)n-butylphenyl,
(o-, m-, p-)sec-butylphenyl,
(o-, m-, p-)tert-butylphenyl,
(2,3-2,4-, 2,5-, 2,6-, 3,4-, 3,5-)dimethylphenyl,
(2,3- 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)diethylphenyl,
2-methyl-3-ethylphenyl,
2-methyl-4-ethylphenyl,
2-methyl-5-ethylphenyl,
2-methyl-6-ethylphenyl,
3-methyl-4-ethylphenyl,
3-methyl-5-ethylphenyl,
2-ethyl-3-methylphenyl,
2-ethyl-4-methylphenyl,
2-ethyl-5-methylphenyl,
3-ethyl-4-methylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-n-propylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)diisopropylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-n-butylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-sec-butylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-tert-butylphenyl,
(2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)trimethylphenyl,
(2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)triethylphenyl,
(2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)tripropylphenyl, or naphtyl.
10. The process of any of claims 1-6, wherein the condensed phosphoric ester is 2,2-bis{4-[bis(phenoxy)phosphoryl]oxyphenyl}propane.
1. Verfahren zur Herstellung von kondensiertem Phosphorsäureester, bei dem
in einer ersten Stufe Bisphenol A Derivat mit Phosphoroxytrihalogenid in einer Menge
gleich oder größer als der 4,5-fachen molaren Menge des Bisphenol A Derivats umgesetzt
wird, um Phosphorhalidat zu bilden;
in einer zweiten Stufe nicht umgesetztes Phosphoroxytrihalogenid nach der ersten Stufe
entfernt wird;
in einer dritten Stufe das in der zweiten Stufe erhaltene Phosphorhalidat mit einer
Verbindung auf Monophenolbasis bei einer Temperatur gleich oder niedriger als 120°C
umgesetzt wird; und
in einer vierten Stufe das Phosphorhalidat mit der Verbindung auf Monophenolbasis
bei einer Temperatur gleich oder höher als 120°C umgesetzt wird.
2. Verfahren nach Anspruch 1, bei dem die Menge an Phosphoroxytrihalogenid die 5- bis
8-fache, vorzugsweise die 5,4-bis 6-fache Menge des Bisphenol A Derivats ist.
3. Verfahren nach Anspruch 1 oder 2, bei dem die erste Stufe in Gegenwart von Katalysator
durchgeführt wird, der Aluminiumchlorid, Magnesiumchlorid, Titantetrachlorid oder
andere Lewissäure ist.
4. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die dritte Stufe des Umsetzens
des Phosphorhalidats mit der Verbindung auf Monophenolbasis bei einer Temperatur von
60 bis 110°C, vorzugsweise 80 bis 100°C erfolgt.
5. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die Gesamtmenge der Verbindung
auf Monophenolbasis, die in der dritten Stufe und der vierten Stufe verwendet wird,
um 2 Mol.% oder weniger über der theoretisch notwendigen Menge liegt, um die gesamte
Menge des Phosphorhalidats in den kondensierten Phosphorsäureester zu überführen.
6. Verfahren nach einem der vorhergehenden Ansprüche, bei dem die Temperatur der vierten
Stufe 120 bis 170°C, vorzugsweise 140 bis 160°C beträgt.
7. Verfahren nach einem der vorhergehenden Ansprüche, bei dem das Bisphenol A oder Derivat
davon durch die Formel
wiedergegeben wird, in der R
5 und R
6, die gleich oder unterschiedlich sein können, jeweils eine Alkylgruppe bedeuten,
die 1 bis 3 Kohlenstoffatome enthält, und n
1 und n
2 jeweils eine ganze Zahl von 0 bis 4 bedeuten.
8. Verfahren nach einem der vorhergehenden Ansprüche, bei dem der kondensierte Phosphorsäureester
eine Verbindung ist, die durch die Formel
wiedergegeben wird, in der R
5, R
6, n
1 und n
2 die in Anspruch 7 angegebenen Bedeutungen haben, n eine ganze Zahl von 1 bis 10 ist
und R
1, R
2, R
3 und R
4, die gleich oder unterschiedlich sein können, jeweils eine Arylgruppe wiedergeben,
die 6 bis 15 Kohlenstoffatome enthält.
9. Verfahren nach Anspruch 8, bei dem R1, R2, R3 und R4 jeweils Phenyl, (o-, m-, p-)-Methylphenyl, (o-, m-, p-)-Ethylphenyl, (o-, m-, p-)-n-Propylphenyl,
(o-, m-, p-)-Isopropylphenyl, (o-, m-, p-)-n-Butylphenyl, (o-, m-, p-)-sec-Butylphenyl,
(o-, m-, p-)-tert.-Butylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)-Dimethylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)-Diethylphenyl, 2-Methyl-3-ethylphenyl, 2-Methyl-4-ethylphenyl,
2-Methyl-5-ethylphenyl, 2-Methyl-6-ethylphenyl, 3-Methyl-4-ethylphenyl, 3-Methyl-5-ethylphenyl,
2-Ethyl-3-methyl, 2-Ethyl-4-methyl, 2-Ethyl-5-methyl, 3-Ethyl-4-methyl, (2,3-, 2,4-,
2,5-, 2,6-, 3,4-, 3,5-)-Di-n-propylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)-Diisopropylphenyl,
(2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)-Di-n-butylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-,
3,5-)-Di-sec-butylphenyl, (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)-Di-tert.butylphenyl,
(2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)-Trimethylphenyl, (2,3,6-, 2,3,5-,
2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-)-Triethylphenyl, (2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-,
3, 4, 5-) -Tripropylphenyl oder Naphthyl bedeuten.
10. Verfahren nach einem der Ansprüche 1 bis 6, bei dem der kondensierte Phosphorsäureester
2,2-Bis{4-[bis(phenoxy)-phosphoryl]oxyphenyl}propan ist.
1. Procédé afin de préparer un ester phosphorique condensé, comprenant :
une première étape de faire réagir un dérivé de bisphénol A avec un oxytrihalogénure
de phosphore en une quantité égale ou supérieure à 4,5 fois en mole la quantité de
dérivé de bisphénol A afin de préparer un phosphorohalogénate ;
une seconde étape d'enlever le oxytrihalogénure de phosphore non réagi après la première
étape ;
une troisième étape de faire réagir le phosphorohalogénate obtenu dans la seconde
étape avec un composé à base de monophénol à une température égale ou inférieure à
120 °C ; et
une quatrième étape de faire réagir le phosphorohalogénate avec un composé à base
de monophénol à une température égale ou supérieure à 120 °C.
2. Procédé de la revendication 1, dans lequel la quantité d'oxytrihalogénure de phosphore
est 5-8 fois en moles, préférablement 5,4-6 fois en moles, la quantité de dérivé de
bisphénol A.
3. Procédé de la revendication 1 ou 2, dans lequel la première étape est effectuée en
présence d'un catalyseur qui est du chlorure d'aluminium, du chlorure de magnésium,
du tétrachlorure de titane ou un autre acide de Lewis.
4. Procédé selon l'une quelconque des revendications précédentes, dans lequel la troisième
étape de faire réagir le phosphorohalogénate avec un composé à base de monophénol
est à une température de 60-100 °C, préférablement de 80-100 °C.
5. Procédé selon l'une quelconque des revendications précédentes, dans lequel la quantité
totale du composé à base de monophénol utilisé dans la troisième étape et dans la
quatrième étape est plus grand, égal ou inférieur à 2 % en mole, que la quantité théoriquement
nécessaire afin de transformer la quantité totale de phosphorohalogénate en l'ester
phosphorique condensé.
6. Procédé selon l'une quelconque des revendications précédentes, dans lequel la température
pour la quatrième étape est de 120-170 °C, préférablement de 140-160 °C.
7. Procédé selon l'une quelconque des revendications précédentes, dans lequel le bisphénol
A ou un dérivé de celui-ci est représenté par la formule :
dans laquelle R
5 et R
6 qui peuvent être les mêmes ou différents représentent chacun un groupe alkyle contenant
1-3 atomes de carbone et n
1 et n
2 représentent chacun un nombre entier de 0 à 4.
8. Procédé selon l'une quelconque des revendications précédentes, dans lequel l'ester
phosphorique condensé est un composé représenté par la formule :
dans laquelle R
5, R
6, n
1 et n
2 ont les significations données dans la revendication 16, n est un nombre entier de
1 à 10 et R
1, R
2, R
3 et R
4 qui peuvent être les mêmes ou différents représentent chacun un groupe aryle contenant
6-15 atomes de carbone.
9. Procédé de la revendication 8, dans lequel R
1, R
2, R
3 et R
4 représente chacun
un phényle,
un (o-, m-, p-)méthylphényle,
un (o-, m-, p-)éthylphényle,
un (o-, m-, p-)n-propylphényle,
un (o-, m-, p-)isopropylphényle,
un (o-, m-, p-)n-butylphényle,
un (o-, m-, p-)sec-butylphényle,
un (o-, m-, p-)tert-butylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)diméthylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)diéthylphényle,
un 2-méthyl-3-éthylphényle,
un 2-méthyl-4-éthylphényle,
un 2-méthyl-5-éthylphényle,
un 2-méthyl-6-éthylphényle,
un 3-méthyl-4-éthylphényle,
un 3-méthyl-5-éthylphényle,
un 2-éthyl-3-méthylphényle,
un 2-éthyl-4-méthylphényle,
un 2-éthyl-5-méthylphényle,
un 3-éthyl-4-méthylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-n-propylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-) diisopropylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-n-butylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-sec-butylphényle,
un (2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-)di-tert-butylphényle,
un (2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-) triméthylphényle,
un (2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-) triéthylphényle,
un (2,3,6-, 2,3,5-, 2,3,4-, 2,4,5-, 2,4,6-, 3,4,5-) tripropylphényle, ou un naphtyle
10. Procédé selon l'une quelconque des revendications 1 à 6, dans lequel l'ester phosphorique
condensé est du 2,2-bis{4-[bis(phénoxy)phosphoryl]oxyphényl}propane.